1) What kind of underwear does your character wear? Tighty whities? Boxer briefs? Bikini? Commando? Underwear choice says a lot about a person.
2) If your character saw a penny laying on the ground, would they stoop to pick it up? Would they pick it up only if it were "heads up" because they are superstitious? Would they pick it up because they were so broke that they needed a measly penny? Would they step over it? Would they miss it completely because they have their head in the clouds?
3) Who would your character take a bullet for? Their family? A friend? What about their boss? How about a complete stranger? Nobody?
Obviously, your reader doesn't need to know your answers. (Unless you are writing romance, in which case, question number one may be of paramount importance.) However, the better able YOU are to answer these things then the more rich and complex your character will ultimately be!
Happy writing!!
Some days, you can find Beth here: bethnbijoux